Basic imaging properties in a computed radiography system

Basic imaging properties in a computed radiography system (FRC-101), such as the dose absorption rate, relative intensities of instantaneous and photostimulated light, spatial resolution and noise properties, were measured. Three different versions of the photostimulable phosphor plate (image plate, IP), types I, II and III of ST and types II and III of HR were investigated. The presampling MTFs as an inherent resolution property in a digital system were measured for resolution analysis. Digital Wiener spectra were calculated for noise analysis. Moreover, the observer performance experiments with a Burger phantom, for types II and III of ST, were examined. Results showed that with the improvement of IPs, the instantaneous emission decreases, while the photostimulated emission increases considerably (approximately 1.8 and 1.7 times for ST and HR, respectively). A comparison of the different versions of IP showed an insignificant change in spatial-resolution properties but a significant improvement in noise. The detectability of low-contrast objects in type III was slightly better than that in type II. (author)